Process for the manufacture of torque stretch yarn



Oct. 13, 1964 c. J. DUDZIIK. ETAL PROCESS FOR THE MANUFACTURE OF TORQUE STRETCH YARN 2 Sheets-Sheet 1 Filed April 10. 1961 ATTYS.

PROCESS FOR THE MANUFACTURE OF TORQUE STRETCH YARN Filed April 10, 1961 Oct. 13, 1964 c. J. DUDZIK ETAL 2 Sheets-Sheet 2 m m 2 T E T M 6 w Hwm A 6 6 4 .m 6 A i 2%... E r m F Y V/////// M Q M, m b .M H. a 3 M w W G. 7 5 J4, H 0 a H 5 ,5 4/% il l 4 M l\||\ h m w m&

United States Patent 3,152,436 PRQUESS FQR THE MANUFACTURE OF TGRQUE STRETCH YARN Chester J. Dudzilr, $61 Narragansett Parkway, Warwick, R.l., and Richard G. Hilbert, RAID. 3, Esmond, RI. Filed Apr. 10, 1961, Ser. No. 102,051 4 Claims. (Cl. 57-157) The present invention relates to the manufacture of torque stretch yarn and has particular application to high speed processing of yarn while heated through a false twist spindle which twists the yarn in one direction to thereby reorient the molecules to the twisted formation and thereafter untwists the yarn to cause it to assume a crimped or coiled configuration which imparts inherent elasticity and bullc-iness which is characteristic of torque stretch yarn.

Prior to the present invention, the production of torque stretch yarn was limited by the speed limitations which the conventional apparatus imposes. For example, in the apparatus disclosed in U.S. Patent No. 2,303,109 to Stod- (lard et al., the normal operating speed of the false twist spindle is in the neighborhood of 30,000 rpm. and by design changes in the apparatus, it is possible to elevate the operating speed of the spindle to the neighborhood of 50,000 r.p.m., but the machine limitations render it impossible to elevate the spindle speed beyond that. In the copending US. Patent Application of Hilbert, Serial No. 742,234, filed June 16, 1958, now Patent Number 3,044,247, an improved spindle construction is disclosed which enables the spindle speed to be increased to 150,000 rpm. and with special manufacturing techniques, it is possible to operate selected spindles at a speed of 300,000 rpm. However, prior to the present invention, it was considered to be impossible to raise the processing speed much above the 300,000 r.p.m. limit of the apparatus shown in the aforesaid application.

With the foregoing in mind, it has been found that it is possible to increase the openating speed substantially above 300,000 rpm. by certain modifications of the apparatus which enables accurate control of the processing to produce satisfactory yarn in a fully effective and practical manner.

In addition to the foregoing, it has been found that in the processing of the yarn at high speed, the yarn itself reacts differently than it does at relatively low speeds and effective processing of the yarn requires accurate control of the operational characteristics of the apparatus as well as the condition of the yarn introduced into the apparatus. Such high speed processing also requires a different combination of operational effects in the yarn which were not readily apparent.

With the foregoing in mind, a primary object of the present invention is to provide an improved method for processing yarn into torque stretch yarn at substantially higher speeds than are presently contemplated with convention-al methods.

More specifically, the present invention provides an improved method for processing the yarn wherein the factors of the ambient condition, the friction applied to the yarn, and the operations upon the yarn, are accurately controlled to enable the production of the yarn at the high speed contemplated herein.

All of the objects of the invention are more fully set forth hereinafter with reference to the accompanying drawings wherein:

FIG. 1 is a transverse sectional view through a multistation apparatus adapted to pnactice the present invention;

FIG. 2 is a fragmentary view in front elevation with portions broken away showing two of the multiple stations for the processing of the yarn;

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FIG. 3 is a sectional view through the spindle shown in FIGS. 1 and 2, said view being taken on the irregular section line 3-3 of FIG. 4;

FIG. 4 is a transverse sectional view taken on the line 4-4 of FIG. 3;

FIG. 5 is an enlarged plan view of the spindle head shown in FIG. 3; and

FIG. 6 is an enlarged sectional view taken on the line 6-6 of FIG. 3.

With reference to the drawings, the preferred apparatus for carrying out the present invention comprises a multistation machine, each station including two false twist spindles, each having a separate yarn supply, a pair of spaced-apart cooperating feed rolls to apply a preselected degree of tension to the yarn, a heated zone and a false twist spindle for the tensioned yarn intermediate the pair of feed rolls, and a take-up. The feed stations are disposed side by side along the front and along the black of the apparatus, and the drives for the respective feed rolls, the false twist spindles, and the take-ups are coordinated by conventional drive means (not shown) to correlate the linear speed of travel of the yarn with the rotational speed of the false twist spindle to insert the desired twist into the yarn. The heated zones are likewise correlated to the linear travel of the yarn to supply sufficient heat thereto to effect the proper yarn setting which reorients the molecules of the yarn in the twisted formation to produce the crimped or coil-like configuration that is characteristic of torque stretch yarn.

Preferably, the heater 14 is approximately 28 inches long and has a radius of curvature in the neighborhood of 44 feet and is regulated to the temperature at which the yarn is desired to be processed, the length of the heater enabling the yarn to reach equilibrium temperature with the heater as it travels thereover. Thus, the temperature of the heater is maintained uniformly at 'a point below the temperature at which the yarn melts by heat. It has been found possible to employ a contact heater whereby the yarn is heated by contact with the heater plate, or alternative heaters may be used such as radiant heaters wherein the yarn never contacts the heating element but the heating takes place by radiation.

In the present instance, the raw yarn is supplied fnom supply packages 10 mounted at the base of the machine for over-end delivery through a pig-tail guide 11 and over a guide rod 12 to the lower feed rolls 13. The yarn Y is wrapped around the feed roll means 13 and passes upwardly over the face of a heater plate 14 which in the present instance is electrically controlled to accurately regulate the amount of heat imparted to the yarn during its travel thereover. It should be noted that in FIG. 1, the yarn Y is out of contact with the heater face so that it may be readily threaded through the spindle which is in inoperative position for the threading operation. A threading device 15 is operatively associated with the heater 14 to facilitate the threading :of the yarn through the groove or slot 16 provided in the insulated face of the heater 14 in order to provide a rapid and efficient threading of the apparatus during the initial set-up of the machine and in the event of yarn breakage during the operation of the machine. The details of the threading device are set forth in more 'detail in the copending US. patent application Serial No. 98,811 filed March 28, 1961 in the name of Chester J. Dudzik for Yarn Guiding Device, now Patent Number 3,094,761.

From the heater 14, the yarn passes through the false twist spindle 18 which is constructed as more fully set forth hereinafter. The spindle 18 is mounted for rotation on a swing arm 19 and is adapted to be swung from the inoperative position shown in FIG. 1 into the operative position in engagement with the drive belt 20. The swing arm 19 may be constructed as set forth in the co- =1 pending US. patent application, Serial Number 100,875 filed April 5, 1961 of Richard G. Hilbert for False Twist Spindle Assembly, now US. Patent Number 3,074,226 to provide selective positioning of the spindle 18 on either side of the drive belt 2t) so as to afford opposite directions of rotation of the spindle with correspondingly opposite directions of false twist and resulting twist-torque in the finished yarn.

From the false twist spindle 18, the yarn passes around the upper feed roll means 22 which is driven in coordination with the feed roll means 13 and cooperates therewith to provide a preselected degree of tension in the yarn between the upper and lower feed rolls. If desired, the upper feed rolls may be mounted for simplified threading in the manner disclosed in the copending US. patent application, Serial No. 101,106 filed April 6, 1961 of Raymond V. Tata for Feed Rolls, now Patent Number 3,119,572.

From the feed rolls 22, the yarn Y is passed to the respective take-ups 23 and 23a for the right and left yarns in the processing station. The take-ups 23 and 23a are positioned to the front of the machine respectively above and below the upper feed rolls 22. By this arrangement, it is possible to provide an enlarged take-up package coextensive in width with the station without having the yarn to one package interfering with the yarn to the other package during the take-up.

Each of the take-ups 23 includes a guide rod 24 over which the yarn from the feed roll 22 passes. A traverse 25 engages the yarn passing over the guide rod 24 to position it on the take-up roll 26 so as to provide a level wind thereon. The take-up roll 26 is driven by a drive roll 27 which withdraws the yarn at a uniformly constant rate regardless of the size of the take-up package 26. It is apparent that during the threading operation, the threading of the yarn onto the take-up 23 is unobstructed by the yarn passing to the take-up 23a, and vice versa. In order to provide uniformity between the yarns advanced to the respective take ups, it has been found important to insure that the span of yarn between the feed roll 22 and the guide rod 24 is substantially equal in each of the take-ups. Thus, as shown in FIG. 1, the span of yarn Y between the upper feed roll 22 and the guide rod 24 of the take-up 23 is substantially equal to the span Y" of yarn between the feed rolls 22 and the guide rod 24 of the take-up 23a in this manner. The yarn leaving the feed rolls 22 is subjected to the same freedom for relaxation, and is subjected to the condition of the room air for precisely the same time and to the same extent as the yarn traveling to the take-up 23a. In this way, the yarns throughout the finished take-up packages 26 are uniform, regardless of whether the take-up package comes from the take-up 23 or the take-up 23a. This feature is extremely important when subjecting the yarn to high speed processing since the yarn which may be traveling at up to 150 yards per minute is highly sensitive to changes in ambient temperature or humidity conditions, even as it reaches the take-up packages. This is opposed to the conventional slow speed processing wherein the yarn on the take-up package has had sufficient opportunity to reach equilibrium with the ambient conditions surrounding the apparatus well in advance of the time when it is wound on the take-up package.

The spindle 18 is constructed to operate efliciently and effectively at the high speed to insert the necessary false twist in the yarn as it is traveling therethrough at the high speed without imposition of excessive tension thereto. To this end, the spindle 18 comprises a small light-weight spindle blade 31 mounted for rotation in a generally C-shaped housing 32 secured to the swing arm 19. The spindle blade is journalled adjacent its upper and lower ends respectively in the upper and lower leg portions 33 and 34 respectively of the Ct-shaped housing 32. To this end, the upper and lower terminal ends of the blade are provided with external surfaces 35 and 36 which comprise surfaces of rotation coaxial with the spindle, in the present instance being cylindrical. Between the surfaces 35 and 36 is a whorl 37 of cylindrical form having a greater diameter than the diameter of the surfaces 35 and 36 to provide, intermediate the bearing surfaces 35 and 36, tapered shoulders 39 and 40 respectively. Journal bearings 41 and 42 are mounted in the leg portions 33 and 34 respectively to provide a substantially friction-free mounting for the spindle blade therein.

The journal bearings 41 and 42 are similar in form and comprise a collar 4-5 of porous material, for example sintered bronze or the like. The collar 45 is mounted in a bore 46 of the upper portion 33 in contact with an annulus 47 of wicking which serves to maintain the collar 45 impregnated with lubricant. The lubricant is supplied to the annular wick 47 from a reservoir 48 having suitable packing 49 therein to which lubricant is supplied through a suitable supply aperture 50. Although the spindle does not contact the collar 45 in normal operation, the impregnation of the collar with lubricant is sufiicient to maintain the surface 35 lubricated.

The journal surface 35 of the spindle bears against bearing elements 53 and 54 mounted in radial slots 55 and 56 in the collar 45. The bearing elements 53 and 54 are of similar form and comprise a fiat planar wall 52 disposed parallel to the axis of the spindle blade so as to provide a substantially line-contact between the bearing element and the spindle bearing surface 35. The wall 52 terminates at one end in an angled bearing surface 51. The opposite surface of the bearing element 54 is arcuate and abuts a bearing plate 58 seated against the bottom wall 59 of the radial recesses 56 as shown. The arcuate form of the bearing element 54 enables the flat bearing surface 52 thereof to adjust itself into parallelism with the spindle axis and insure proper line contact between the flat surface 52 and the spindle surface 35. Each of the bearing elements is preferably formed of a hard wear-resistant material such as tungsten carbide.

The bearing elements 54 and 53 are disposed at an angle to one another less than degrees and in the present instance are symmetrically spaced adjacent to but in spaced relation from the center line of the intermediate portion of the C-shaped housing 32 and are anchored in that position by a pin 58 passing through the leg 33 of the housing.

In normal operation, the swing arm 19 which mounts the housing 32, biases the spindle against the drive belt 20 so that the belt seats the spindle blade against the respective bearing elements at the upper and lower ends of the spindle blade. The spindle blade is held against downward axial displacement by engagement of the shoulder 40 against a complementarily angled surface on the bearing elements in the lower journal bearing 42. Upward axial displacement is limited by the engagement of the shoulder 39 against the confronting angled bearing surface.

In order to insure continuous trouble-free performance, it has been found necessary to machine the spindle blade from bar stock as opposed to swaging or machining the same from tubular stock. To this end, the surfaces 35, 36 and 37 and the surface of bore 61 of the spindle blade are machined into precise cylindrical form coaxially with the blade. The drilling of the bore into the bar stock and the machining of the outer surfaces provide a spindle whose metallic structure is extremely durable and does not disintegrate or fly apart during the extremely high speed rotation which is characteristic of the present invention. The material from which the spindle is formed is preferably ball bearing steel Which, in itself is highly resistant to Wear and is of extreme hardness and durability.

In order to trap the twist in the yarn effected by rotation of the spindle, without applying substantial tension to the yarn, a twist trapper is provided at the upper end of the spindle. In the present instance, the twist trapper comprises a tubular spindle head 62 of aluminum or similar light-weight material. The spindle head 62 is of hollow cylindrical form which is cut away at its top at diametrically opposite points to provide upstanding ears 63 and 64. The ears are provided with tapped apertures 65 and 66 therein which are in precise transverse alignment to receive therein a twist trapping pin 67. As shown in FIGS. 3 and 5, the pin 67 has cylindrical end portions 68 and 69 which are cemented in the apertures 65 and 66 of the ears 63 and 64. The cementing of the pin in the apertures provides a firm bond without danger of cracking or otherwise damaging the pin which is preferably formed of a hard wear-resistant material such as aluminum oxide to minimize the tension applied to the yarn by the pin. The central portion of the pin is reduced in thickness to provide a throat for receiving the yarn Y passing upwardly through the spindle, and centering it therein. In order to reduce the resistance applied to the yarn by the pin 67, the diameter of the pin is chosen as large as possible without losing the twist trapping properties of the pin. It has been found that a pin of inch diameter is highly effective to trap the twist Without applying excessive friction to the yarn. To this end, as seen in FIGS. 5 and 6, the diameter of the throat of the pin 67, is slightly less than the internal diameter of the bore 61 which insures that the pin maintains the yarn in spaced relation to the internal wall of the bore as it passes through the spindle.

The invention assures proper processing of the yarn by maintaining the frictional drag on the yarn at a minimum. The twist trapping pin imparts somewhat less than 30 grams tension on the yarn above the spindle when the spindle is rotating at 350,000 rpm, and proper operation of the apparatus requires that this frictional drag be maintained uniformly.

It should be noted that by using a spindle head of lightweight material such as aluminum and the like, any flexure of the head imparted thereto by the pin or the yarn on the pin, has little or no effect on the rotational balance of the spindle itself.

Thus, from the foregoing, it is apparent that the present invention provides a process wherein the frictional forces on the yarn and in the apparatus are maintained at a minimum. The upward travel of the yarn through the spindle and around the twist trapping pin provides an upward component of force which acts in opposition to the weight of the spindle and thereby minimizes the load on the shoulders above and below the whorl. In order to insure proper continuous uninterrupted operation with the resulting assurance of uniformity in the processed yarn, it is necessary to maintain close tolerances which eliminates eccentric rotation of the spindle and maintains the pin in precise alignment with the spindle bore.

In order to insure continued operation, it has also been found necessary to maintain the humidity of the surrounding atmosphere above 40% relative humidity, as otherwise excessive breakage of the yarn occurs which necessitates frequent shut-down of the various spindles and with the result that the finished yarn on said spindles is not substantially uniform throughout. It will be appreciated that any suitable humidifying apparatus may be arranged integrally with the apparatus of the present invention, or humidity control may be provided for the 6 surrounding atmosphere from a unit remote from said apparatus.

When operating the apparatus at between 360,000 and 400,000 r.p.m., using denier nylon yarn, the travel of the yarn is in the neighborhood of to yards per minute which means that a section of yarn is traveled from the supply package to the take-up package in less than one second. Accordingly, it is necessary to maintain proper conditions throughout the process since there is little opportunity for the yarn to reach equilibrium condition with the surrounding atmosphere during the travel.

While a particular embodiment of the present invention has been herein illustrated and described, it is not intended to limit the invention to such disclosure, but changes and modifications may be made therein and thereto within the scope of the following claims.

We claim:

1. A process for the manufacture of torque stretch yarn wherein the yarn is continuously heated and falsetwisted under a controlled degree of tension, to be set While twisted, while being advanced at a high linear speed, comprising the steps of withdrawing unprocessed yarn from a supply package at a uniform high speed, and uniformly tensioning the yarn to a preselected degree of tension in one portion of its travel, passing the yarn through a heated zone whereby the yarn traveling through the heated zone at high speed reaches heat-transfer equilibrium therewith and assumes the temperature thereof, engaging the traveling yarn with a twist trapping device and rotating said device and thereby said yarn about the yarn axis at a speed in the neighborhood of 350,000 revolutions per minute to thereby insert twist into the traveling yarn below said device and remove the inserted twist above said device, the inserted twist being present in the yarn as it travels through the heated zone to thereby reorient the molecules of the yarn to the twisted formation, maintaining the drag imposed on the yarn by said twist trapping device substantially below 30 grams tension, and withdrawing the yarn and winding the same on a take-up package at a speed commensurate with the high speed of travel of said yarn through said heated zone and through said spindle.

2. A process according to claim 1 including the step of maintaining the ambient humidity above 40 percent relative humidity during said withdrawal of the yarn and the winding thereof on the take-up package.

3. A process according to claim 1 wherein the temperature of the heated zone is maintained uniformly at a point below the temperature at which the yarn melts.

4. A process according to claim 1 wherein the maintenance of the drag imposed on the yarn by the twist trapping device is effected by wrapping the yarn around a pin of hard, wear-resistant aluminum oxide having an approximately inch diameter.

References Cited in the file of this patent UNITED STATES PATENTS 2,777,276 Klein Jan. 15, 1957 2,855,750 Schrenk et a1 Oct. 14, 1958 2,863,277 Boillat et al Dec. 9, 1958 2,936,570 Arthur et a1 May 17, 1960 2,968,909 Comer et a1. Ian. 24, 1961 2,991,614 Ubbelohde July 11, 1961 3,044,247 Hilbert July 17, 1962 

1. A PROCESS FOR THE MANUFACTURE OF TORQUE STRETCH YARN WHEREIN THE YARN IS CONTINUOUSLY HEATED AND FALSETWISTED UNDER A CONTROLLED DEGREE OF TENSION, TO BE SET WHILE TWISTED, WHILE BEING ADVANCED AT A HIGH LINEAR SPEED, COMPRISING THE STEPS OF WITHDRAWING UNPROCESSED YARN FROM A SUPPLY PACKAGE AT A UNIFORM HIGH SPEED, AND UNIFORMLY TENSIONING THE YARN TO A PRESELECTED DEGREE OF TENSION IN ONE PORTION OF ITS TRAVEL, PASSING THE YARN THROUGH A HEATED ZONE WHEREBY THE YARN TRAVELING THROUGH THE HEATED ZONE AT HIGH SPEED REACHES HEAT-TRANSFER EQUILIBRIUM THEREWITH AND ASSUMES THE TEMPERATURE THEREOF, ENGAGING THE TRAVELLING YARN WITH A TWIST TRAPPING DEVICE AND ROTATING SAID DEVICE AND THEREBY SAID YARN ABOUT THE YARN AXIS AT A SPEED IN THE NEIGHBORHOOD OF 350,000 REVOLUTIONS PER MINUTE TO THEREBY INSERT TWIST INTO THE TRAVELING YARN BELOW SAID DEVICE AND REMOVE THE INSERTED TWIST ABOVE SAID DEVICE, THE INSERTED TWIST BEING PRESENT IN THE YARN AS IT TRAVELS THROUGH THE HEATED ZONE TO THEREBY REORIENT THE MOLECULES OF THE YARN TO THE TWISTED FORMATION, MAINTAINING THE DRAG IMPOSED ON THE YARN BY SAID TWIST TRAPPING DEVICE SUBSTANTIALLY BELOW 30 GRAMS TENSION, AND WITHDRAWING THE YARN AND WINDING THE SAME ON A TAKE-UP PACKAGE AT A SPEED COMMENSURATE WITH THE HIGH SPEED OF TRAVEL OF SAID YARN THROUGH SAID HEATED ZONE AND THROUGH SAID SPINDLE. 